A voltage-controlled oscillator (VCO) is a device typically used in phase-locked loop (PLL) circuits to provide an output clock signal that is phase locked to a reference clock signal. The VCO has an output frequency that can be adjusted by varying a control voltage input. The voltage-to-frequency gain, also referred to as tuning slope, of the VCO specifies the amount of frequency change that results from a given change in the control voltage. The tuning slope is typically represented by the symbol “Kv” and expressed in units of Hz/V. In an ideal VCO, the tuning curve is linear and the tuning slope is constant. VCO devices that are of the inductor-capacitor (LC) type have generally non-linear curves of output frequency versus control voltage due to the non-linear characteristics of the varactors used in the LC-VCO.